An Investigation of Thermo-Mechanical Finite Element Analysis Methodologies and a Demonstration on the Case of a Small-Scale Composite Cryogenic Hydrogen Tank

With the aim of reducing and eventually eliminating CO2 emissions, the aviation industry is investigating alternative fuels, with liquid hydrogen (LH2) being one of the most promising. Several research projects that deal with the subsystem design of liquid hydrogen aircraft have commenced, with specific attention given to the development of lightweight cryogenic tanks. Composite materials are potential candidates for cryogenic aviation applications, yet they experience issues with thermal stresses that result to various types of damage that should be thoroughly investigated, to enable reliable composite cryogenic structures. In this direction, the present work investigates the alternative finite element techniques for the thermo-mechanical analysis of the characteristic geometrical structural configuration. Thermo-mechanical stress analysis results derived from the investigated analysis methodologies are verified by their comparison to published results. The assessment of the alternative modeling techniques contributes to the adaptation of the FE modeling development strategy to the desired analysis type and the expected results and is directly applicable to the thermo-mechanical design of cryogenic components. The outcome of the investigation is demonstrated in the case of thermo-mechanical analysis of an outer tank of an LH2 storage system, performed with the optimal combination of shell and solid elements.